While much of the Pi's previous research has been peripherally related to biomedicine, it was all done as an engineer's approach to solve biomedical problems, focusing on development of new engineering approaches (i.e. materials, fluidic device, imaging techniques, and mechanical conditioning) to tackle tissue in vitro from a viewpoint of mechanical engineering, based on only a basic understanding of biomedical situation. The proposed training opportunity would provide the PI with an in-depth knowledge of vascular pathology, cell signal transduction, animal and clinical experimentation, as well as added knowledge in imaging, fluid dynamics and mechanobiology in the context of vascular medicine. The career development plan proposed here will greatly help the PI grow in a trans-disciplinary field at the intersection of flow dynamics, cell molecule biology, and vascular medicine. Arterial stiffening is recognized as an important factor of cardiovascular events and increased arterial pulse pressure, a direct consequence of stiffening, has been used to guide pharmaceutical treatment for a variety of systemic vascular diseases. The overall hypothesis of the research project is that increased stiffness of large pulmonary arteries contributes to structural and functional alterations in distal pulmonary arteries, characteristics of pulmonary arterial hypertension, and stiffened arteries play such a pathogenic role in vascular diseases via the modulation of flow pulsatility which causes and/or perpetuates inflammation and thrombosis in the distal PA circulation. To test this hypothesis, three specific aims will be studied: (1) Determine the relationship between pulmonary arterial stiffness and flow pulsatility in hierarchical pulmonary vasculature; (2) Determine effects of flow pulsatility on functional activation of PA endothelial cells; and (3) Determine the molecular mechanisms in flow-induced endothelial activation. RELEVANCE (See instructions): This research program will explore a new mechanism to improve understanding pulmonary vascular diseases. Insights into the mechanism may facilitate development of novel diagnostic and therapeutic strategies that offer an improved quality of life and increased survival rate of affected patients. (End of Abstract)